Presently, in the 3GPP (Third Generation Partnership Project), the standardization of LTE-advanced (hereinafter the LTE Release 10 specifications and the specifications of later versions will be collectively referred to as “LTE-A”), which is an evolved radio interface of the LTE (Long Term Evolution) Release 8 specifications (hereinafter referred to as “LTE” or “Rel. 8”) is in progress. LTE-A is attempting to realize higher system performance than LTE while maintaining backward compatibility with LTE.
Also, in LTE-A, a micro cell (for example, a pico cell, a femto cell, and so on), which has a local coverage area of a radius of approximately several tens of meters, is formed in a macro cell, which has a wide coverage area of a radius of approximately several kilometers. A network configuration such as this in which nodes of different powers are overlaid is referred to as a “HetNet” (Heterogeneous Network) (see, for example, non-patent literature 1). A normal radio base station to form a macro cell will be hereinafter referred to as a “macro base station,” and a pico base station or a femto base station of lower transmission power will be hereinafter referred to as a “small transmission power node.” Small transmission power nodes include a base station antenna apparatus (RRH: Remote Radio Head). A base station antenna apparatus is a small transmission power node that is set in a distant location from a macro base station using optical fiber and so on, and forms a micro cell under control of a macro base station.